private static bool TryReadQuality(StringSegment input, StringWithQualityHeaderValue result, ref int index)
{
var current = index;
// See if we have a quality value by looking for "q"
if ((current == input.Length) || ((input[current] != 'q') && (input[current] != 'Q')))
{
return(false);
}
current++; // skip 'q' identifier
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
// If we found "q" it must be followed by "="
if ((current == input.Length) || (input[current] != '='))
{
return(false);
}
current++; // skip '=' separator
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
if (current == input.Length)
{
return(false);
}
if (!HeaderUtilities.TryParseQualityDouble(input, current, out var quality, out var qualityLength))
{
return(false);
}
result._quality = quality;
current = current + qualityLength;
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
index = current;
return(true);
}
private static int GetStringWithQualityLength(StringSegment input, int startIndex, out StringWithQualityHeaderValue parsedValue)
{
Contract.Requires(startIndex >= 0);
parsedValue = null;
if (StringSegment.IsNullOrEmpty(input) || (startIndex >= input.Length))
{
return(0);
}
// Parse the value string: <value> in '<value>; q=<quality>'
var valueLength = HttpRuleParser.GetTokenLength(input, startIndex);
if (valueLength == 0)
{
return(0);
}
StringWithQualityHeaderValue result = new StringWithQualityHeaderValue();
result._value = input.Subsegment(startIndex, valueLength);
var current = startIndex + valueLength;
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
if ((current == input.Length) || (input[current] != ';'))
{
parsedValue = result;
return(current - startIndex); // we have a valid token, but no quality.
}
current++; // skip ';' separator
current = current + HttpRuleParser.GetWhitespaceLength(input, current);
// If we found a ';' separator, it must be followed by a quality information
if (!TryReadQuality(input, result, ref current))
{
return(0);
}
parsedValue = result;
return(current - startIndex);
}
public static bool TryParse(StringSegment input, out StringWithQualityHeaderValue parsedValue)
{
var index = 0;
return(SingleValueParser.TryParseValue(input, ref index, out parsedValue));
}